The Vertex and Axis Symmetry of a Quadratic Function is the form where a,b, and c are real numbers and a is not equal to zero.
f(x) = ax^2 + bx + c

The Domain of a Quadratic function is the set of all real numbers.

f(x) = -x^2 + 4x +5 graph:

vertex_and_axis_symmetry.png